Shock Theater usually aired on late night television on weekends with a costumed horror host;[1] a well-known example was Zacherley (John Zacherle) on Philadelphia's WCAU-TV (as 'Roland'), 1957–1958, and New York'sWABC-TV, 1958–1959. Prior to Zacherely's arrival at WABC-TV, Shock Theater was hosted off-camera by ABC Staff Announcer Scott Vincent. Shock Theater continued the American tradition of horror film television shows that originated with Vampira (Maila Nurmi) at Los AngelesKABC-TV 1954–1955. Shock Theater programs in major cities were often introduced by local hosts in the style of Zacherley or Vampira.

One of the most innovative of the series was produced during 1962-63 at the Los Angeles Television station KTLA-TV which was owned by Gene Autry. Gene Autry brought in Bill Aken as musical director and overall producer. Aken re-vamped the commercial breaks making them as entertaining as the films themselves. With spooky music and actors costumed as monsters such as Frankenstein and Dracula, the commercials for sponsor Baldwin Chevrolet took on a whole new aspect. Host Joe Salazar was driven onto the set in an ambulance carrying a coffin which Salazar would emerge from to start the show. Joined by 'Monsters' in all the Chevrolet commercials, with a special theme song, the show garnered an avid fan base all over the Los Angeles area during the two years it was on the air.

Screen Gems acquired a 10-year lease of the television rights to 550 Universal Pictures features in June 1957, with the intention of packaging them by formats and stars, including horror, crime, and comedy.[2] The first Shock package was an instant success nationwide. Viewership measurements in five key television markets (New York, Los Angeles, San Francisco, Philadelphia, San Antonio) showed the program boosting ratings anywhere from 38 percent to 1,125 percent.[3]

Since 1957, Shock Theater has become a generic term, referencing either late night television showings of horror films in general or the genre of early horror films with their emphasis on spooky mood and implied horror, as opposed to the explicitly graphic horror films that followed.